1. Field of the Invention
The invention relates to a fastener for use in an ornament that includes the fastener.
2. Description of the Related Art
Conventionally, in a fastener for use in an ornament, for example, in a pierced earring fastener (pierced earring fastener), a silicone rubber having rubber elasticity is formed in a cylindrical shape, a spherical shape, or a semispherical shape and the like, and a through hole is provided along a center axis thereof. In such a pierced earring fastener, after a shaft-shaped pin of a pierced earring has been inserted into an earlobe, the pin is inserted into a through hole of the pierced earring fastener, and is used as a pierced earring fastener. However, because the silicone rubber is soft, there has been a problem that a pinching force of the fastener is lost within a short period of time; and the fastener is lost or cannot be used properly. Therefore, the Inventor proposed a fastener such as a pierced earring fastener formed by covering a spherically or cylindrically-shaped pinching member for pinching the pin of the pierced earring with a rubber-like member (refer to patent document 1).
Patent Document 1
Japanese Patent Application Laid-open No. 2000-125911
According to the fastener disclosed in patent document 1, pinching capability of a pin (pinched portion) can be continuously maintained, and predetermined advantageous effect have been successfully attained in improvement of durability. However, the rubber-like elastic member is easily expanded due to aging. Therefore, there is a risk that the pinching capability of the pin is lowered, and the fastener drops. Such aging can occur, of course, when mounting and demounting actions are repeated, and even while the pin is inserted in the through hole and maintained there.